Sound reproducing apparatus



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April 21, 1936. H. A. WHEELER ET AL SOUND REPRODUCING APPARATUS Filed April 10, 1955 ATTORNEY.

Patented Apr. 21, 1936 UNITED STATES PATENT OFFICE sotnm anraonuomo msaa'ru 11mm s. Wheeler, .Great Neck, and wuum o. Swinyard, Bayslde, N. Y., alllgnors to Haaeltine Corporation, a corporation of Delaware Application April 10, 1935, Serial No. 15,548

13 Clalms.-

This invention relates to sound-reproducing apparatus. The invention is particularly concerned with such "apparatus as is now generally used in connection with radio broadcast receivers and which includes a sound reproducer of the type having a cone or-diaphragm of relatively large area.

In attempting to provide a uniformly.eifective distribution of reproduced sound waves, through- 1 out a room or auditorium where the reproducing apparatus is employed, and to avoid so-called directional. effects, distortions, and interference patterns, certain diiliculties are met with due to the nature of certain parts of therepro- 15 ducing apparatus employed and to certain peculiarities of behavior-of the. sound waves radiated by reproducers of the type mentioned.

More particularly, while the employment of a sound cavity in connection with a reproducer of.

2c the type mentioned, throughwhich cavity the sound waves are radiated, has certain desirable effects, including the properloadingof the reproducer diaphragm and the amplification of the sound waves, such cavities as have heretofore so-called "directional effects" which have impaired the uniformity of distribution of the radiated sound waves.

casioned by the angular positions of the sound cavity walls, resulting in such a propagation of the waves as to fail to provide eifective reception at certain locations, particularly locations to the side of the apparatus.

Furthermore, it is well known that sound reproducers of the type having a cone or diaphragm of relatively large area, while in many ways being admirably adapted to the use in question, tend to radiate the sound waves of higher frequencies substantially as a beam, while the lower. frequency waves are radiated substantially spherically, thus resulting in a predomination of the sounds of higher pitch in regions directly in front of. the reproducer and a predomination of the sounds of lower pitch in adjacent regions.

It is also well known that, where a sound cavity of the type before described is employed, the presence of parallel surfaces and edges within or adjacent to the cavity causes, respectively, undesirable refractions and reflections, which in turn 50 result in the setting up of interference patterns and a non-uniform effectiveness of the reproduction of the various sound waves throughout the range of audiblefrequencies, due to the tendency of waves which are so reflected or refracted as to 55 arrive simultaneously at the same location to been employed have caused certain objectionable These results have been 00- either neutralize or reinforce each other, thereby impairing the fldelity of reproduction at different locations.

' An object of the present invention is to provide an improved high-fidelity sound-reproducing ap- 5 paratus whereby sounds will be reproduced and propagated with uniform eifectiveness and fidelity throughout the entire region forward of the reproducer in a room or auditoriumin connection with which the apparatus is employed.

A further object is to provide an apparatus of the character aforedescribed, characterized by simplicity and sturdiness while being symmetrical and so proportioned as to present an artistic appearance.

Other and further objects of and advantages achieved by this invention will be apparent from the following description of a preferred embodi- 'ment thereof which is illustrated in the accompanying drawing. v

In accordance with the present invention, there" is provided an improved sound cavity having an especially wide spread or angular divergence so as to effectively radiate sound waves radiated by a reproducer employed in connection therewith, 25 throughout the entire region forward of. the apparatus in a room where the same is employed.

A deflector is employed in connection with the cavity, so arranged as to effect a diffusion of the higher frequency waves which would otherwise 30 tend to be propagated as a beam in the undesira- I 'ble aforedescribed manner. The various surfaces provided by the cavity walls and deflector walls within thecavlty are so arranged as not only to provide the aforementioned desirable effects, but 35 also to have no parallel surfaces or edges and to thereby avoid the undesirable reflection and refraction effects aforementioned.

The various other features comprised in this invention will be apparent from the detailed de- 40 scription hereinafter set forth.

In the accompanying drawing. Fig. 1 is a perspective view of a radio receiver embodying the sound-reproducing apparatus of this invention;

Fig. 2 isan enlarged front elevation showing the apparatus of the invention separately; F18. 8 is a vertical section on the line III-III of Fig. 2; and Fig. 4 is a horizontal section on the line IV--IV of Fig. 2.

Referring in detail to the drawing, the'receiver illustrated therein, which embodies the present preferred form of the invention, comprises a cabinet indicated generally by the numeral It. In the upper portion of the cabinet a radio receivinl apparatus (not shown) is housed in the convenas form).

mntlllly tional manner. The front of the cabinet below the portion housing the receiving apparatus is open and the side walls Ii of the cabinet at this portion are of reduced width.

A sound cavity, indicated generally by the numeral i2, and separately shown in Figs. 2, 3 and 4, is constructed in the portion of the cabinet below the receiving apparatus. The cavity I2 is of conical, pyramidal or polyhedral from, truncated by the front and side walls of the cavity (the cavity in the embodiment illustrated, for example, being of rectangular-pyramidal form). The axis of the cavity is horizontal, with the apex thereof behind the cavity. acterized by a very wide angle of divergence at its horizontal center plane, as hereinbefore more fully described.

The wall structure deflning the sound cavity is secured to the walls of the cabinet by suitable means (not shown). Vertical brace members or posts I! are provided at each corner of the cabinet and may, if desired, extend the entire height thereof An opening H is provided in the wall structure of the sound cavity, preferably in the lower portlon il thereof, which portion slants so as to face in a direction slightly above the horizontal. A

sound reproducer is is disposed behind the cavity opposite the opening. The reproducer is of the type having a cone or diaphragm of relatively large area, the forward edge of its diaphragm ing suitably engaged around the margin of the opening, with the axis of the diaphragm disposed perpendicularly to the plane of the opening, and in accordance with the foregoing description is inclined forwardly and slightly upwardly.

A deflector, indicated generally by the numera I1, is provided within the sound cavity. The deflector is also of conical, pyramidal or polyhedral form (as, for example, in the embodiment illustrated, the deflector is of rhomblc-pyramidal The axis and apex of the deflector are coincident with the axis and apex, respectively, of the sound cavity. The angle of divergence of the deflector at its horizontal center plane is subless than the angle of divergence of the cavity at this plane, while at the vertical plane of symmetry of the cavity the deflector is preferably tangent therewith, the lower tangent portion of the deflector extending across the opening ll. The "base" of the deflector terminates in the plane of the front of the cabinet, and may be either open or closed.

Two vertical brace members or posts II are provided, one at each side of the deflector, at the front of the cabinet, and may, if desired, extend the entire height thereof. The sides of the deflector are suitably secured to the respective posts II.

The deflector thus divides the cavity into two passageways at its opposite sides, and by virtue of the relative angular arrangement of the cavity and deflector walls no parallel surfaces or edges are provided thereby.

In the operation of the apparatus audio-frequency or sound waves are radiated by the diaphragm of the sound reproducer it through the opening it, into and through the sound cavity. The relative angular arrangement of the walls of the sound cavity provides a divergence which approaches an angle of 180 degrees (in the embodiment illustrated approximately 150 degrees) in the horizontal center plane and a divergence at an angle of approximately 120 degrees in the vertical center plane, and the lateral spread there- The cavity is char- I a structure which aosaass 'vide the uniform distribution and diffusion of the sound waves, in the manner hereinbefore set forth, are concerned. It will be understoodthat in the appended claims the word "conicaP is used in its general sense, and it is intended to include all of the various so-called conical or pyramidal forms as well as all suitable polyhedral or curved forms.

The entire inner surface of the sound cavity serves, in effect, as a baifle, but the main bailling effect is, of course, provided by the portion ll of the cavity wall structure, which slants at an angle of approximately 30 degrees to the vertical, the axis oi the sound reproducer being, as aforedescribed, perpendicular to the surface of this wall. By virtue of this slanting arrangement oi the wall II and the position of the diaphragm, there results a propagation of the sound waves in a direction slightly above the horizontal, that is to say, in the general direction of the heads of listeners in a chamber of average line into which the sound waves are radiated. Upon coming in contact with the diverging slanting surfaces of the deflector, the sound waves of relatively high frequencies, which would otherwise tend to'be propagated substantially as a beam, will be deflected and diffused throughout the area forward of the apparatus so as to provide a substantially uniform distribution thereof, as with the lowfrequency waves. There being no parallel surfaces or opposite edges provided by the cavity and deflector walls, the sound reproduction will be free from distortion, interference patterns and other undesirable effects usually caused by such reflections and refractions. I

The arrangement and construction of the reproducing apparatus, as aforedescribed, presents is characterized not only by sturdiness and simplicity but also by symmetry and artistic appearance. Where desired, 'however, a screen of loosely woven fabric may be provided across either the deflector opening, the cavity openings, or both, in the conventional manner, to protect the apparatus in the cavity.

While an approved embodiment of the apparatus of the present invention has been hereinbefore described, it will be readily apparent that many and various changes and modiflcations in form, structure and arrangement of the parts may be made without departing from the spirit of the invention, and it will be understood that all and any such changes and modiflcations are contemplated as a part of this invention, as defined in the appended claims.

What is claimed is:

l. A high-fidelity sound-reproducing apparatus comprising wall structure defining a sound cavity of conical form with its axis substantially horizontal; a sound reproducer adapted to radiate scund waves into and through said cavity; and a deflector of conical form disposed in said cavity in the path of said sound waves having aosaass horizontal, said cavity diverging in the horizontal center plane through the axis of said cavity at an angle approaching 180 degrees; a sound reproducer adapted to radiate sound waves into and through said cavity; and a deflector of conical form disposed in said cavity in the path of said sound waves, having its axis and apex coincident with the axis and apex of said cavity, the angle of divergence of said deflector being substantially lessthan the angle of divergence of said cavity in said horizontal center plane.

3. A high-fidelity sound-reproducing apparatus comprising wall structure defining a sound cavity-of conical form with its axis substantially horizontal; a sound reproducer adapted to radiate sound waves into and through said cavity; and a deflector of conical form disposed within said cavity in the path of said sound waves, and having its axis and apex coincident with the axis and apex of said cavity, the edges of, said deflector being tangent with the wall structure of said cavity in one plane through the axis of said cavity, and the angle of divergence of said deflector being less than the angle of divergence of said cavity in a plane through the axis of said cavity perpendicular to the first said plane.

4. A high-fidelity sound-reproducing apparatus comprising wall structure defining a sound cavity of conical form with its axis substantially horizontal; a sound reproducer adapted to radiate sound waves'into and through said cavity; and

a deflector of conical form disposed within said cavity in the path of said sound waves, and havv ing its axis and apex coincident with the axis and apex of said cavity, the edges of said deflector being tangent with the wall structure of said cavityin a vertical plane through the axis of said cavity, and the angle of divergence of said deflector being less than the angle of divergence of said cavity in the horizontal plane through the ity in the pathof said sound waves having itsaxis of said cavity.

5. A high-fidelity sound-reproducing apparatus comprising wall structure defining a sound cavity of conical form with its axis substantially horirental; a sound reproducer of the relatively large area cone or diaphragm type adapted to radiate sound waves into and through said cavity; and a deflector ofconical form disposed in said cavaxis and apex coincident with the axis and apex of said cavity, the angle of divergence of said deflector being substantially less than the angle of divergence of said cavity in the horizontal plane through the axis d cavity am denecmr being adapted to diffuse sound waves tending to baradiated through said cavity substantially as a beam, the angle of divergence of said cavity in said horizontal plane through the axis of said cavity approaching 180 degrees, so as to eflect together with the diffusion of said deflector, uniform distribution ofsaid sound waves substantially throughout the entire region forward ofsaid apparatus in 'a chamb er into which said sound waves are radiated. g

6s A high-fidelity sound-reproducing apparatus comprising wall structure deflninga sound cavity ot conical form having its axis substantially waves throughout the entire region forward of said apparatus in a chamber into which said sound waves are radiated and the angle of divergence of said cavity in the vertical plane through the axis of said cavity being substantially less than said angle of divergence in said horizontal plane.

'7. A high-fidelity sound-reproducing apparatus comprising wall structure defining a sound cavity of cdnical form having its axis substantially horizontal, said cavity thereby including a lower wall structure portion facing in an upward direction and said portion having an opening formed therein; and a sound reproducer disposed behind said lower portion with its axis substantially perpendicular thereto and adapted to radiate sound waves through said opening, and into and through said cavity, the angle of divergence of said, cavity wall structure in the horizontal plane through the axis of said cavity approaching 180 degrees, to effect thereby substantially uniform distribution of said sound waves throughout the entire region forward of said apparatus in a chamber into which sound waves are radiated.

8. A high-fidelity sound-reproducing apparatus comprising wall structure defining a sound cavity of conical form having its axis substantially horizontal; a sound reproducer adapted to which said sound waves are radiated and the angle of divergence of said cavity in the vertical plane through the axis of said cavity being substantially less than said angle of divergence in said horizontal plane.

9. A high-fidelity sound-reproducing apparatus comprising wall structure defining a cavity of polyhedral form with its axis substantially horizontal; a sound reproducer adapted to radi- .ate sound waves into and through said cavity;

and a .defiector of polyhedral formdisposed in said cavity in the path of said sound waves having its axis and apex coincident with the axis and apex of said cavity, the angle of divergence of said deflector belng'less than the angle of divergence of said cavity in at least one plane. through the axis of said cavity.

.10. A high-fidelity sound-reproducing appara- I tus comprising wall structure defining a cavity of tetrahedral form with its axis substantially horizontal; asound reproducer adapted to radiate sound waves into and through said cavity; and a deflector of polyhedral form disposed in said cavity in the pathof said sound waves having its axis and apex coincident withthe axis and apex of said cavity, the angle of divergence of said deflector beingless than the angle of divergence of said cavity in at least one plane through the axis of said'cavity.

11. A high-fidelity sound-reproducing apparatus comprising wall structure deflning a cavity of polyhedral form with its axis substantialLv horizontal; a sound reproducer adapted to radiate sound waves into and through said cavity; and a deflector or tetrahedral form disposed in said cavity in the path or said sound waves having its axis and apex coincident with the axis and apex of said cavity, the angle 01 divergence oi said deflector being less than the angle or divergence of said cavity-in at least one plane through the axis of said cavity.

12. A sound-reproducing apparatus symmetrical with respect to a vertical plane, comprising a conical baifle having an opening in its lower side, a cone-diaphragm sound radiator mounted behind said baflle to subtend, and to radiate through, said opening, and a conical deflector, said baflle and deflector diverging toward the front of said apparatus and having a common apex and horizontal axis in said vertical plane, said deflector being tangent to said baflle only in said plane, and said baflie having in any other plane through said axis a greater angle of divergence than said deflector.

13. A sound-reproducing apparatus symmetrical with respect to a vertical plane, comprising a rectangular-pyramidal baflie having an opening in its lower side, a cone-diaphragm sound radiator mounted behind said bame to subtend,

and to radiate through, said opening, and a 

